Temperature control apparatus



March 5 R. c. MAIN TEMPERATURE CONTROL APPARATUS Filed May 20, 194':

ROBERT C Mal/v.

USN

Patented Mar. 13, 1951 UNITED STATES F Robert. 0.. 'Main, Los. Angeles,Calif., .a'ss'ignor, .to

Robertshaw-Fulton Controls Compann a corporation of Delaware ApplicationMay 20, 1947,:SerialNo. 749,259

1 '1 Claim.

This inventionrelates to control apparatus for air conditioning systemsand, more particularly, to apparatus for controlling hotand cold. waterpanel heating and cooling systems.

In my copending application Serial No. 749,258, filed of even dateherewith, now Patent No. 2,519,266 of August,15, 1950, there. isdisclosed a temperature controlzsystem particularly adapted for. panelheating systems utilizing heating fluid circulated from a gas-fired.heater through a mixing valve subject. to control by means responsive tooutdoor temperatures. In this manner, the temperature of the circulatingfluid is maintained proportional to the variations. in outsidetemperature. and the system serves. to meet. all changes in the need forheat. Additionallmprovision is made to overcome the temperature lainherentlinpanel heatingzsystems and to avoid discomfort upon suddenincreases in outdoor temperature, all as fully described in saidcopending application. I

Thepresent invention .has for an object to accomplish similar automatic.control of the tem.- peraturev of the circulating fluid without the useof the special mixing valve disclosed in the aforesaid-application.

Another object. of the invention is to vary the temperature of thecirculating fluid in proportion to the total heating demand asestablished by the outdoor temperature.

Another object of theinventionis to eliminate the hunting effect. due.to inertia of thestructure being heated.

Another objectof the invention is to utilizethe outdoor controlapparatus for selecting the basic energy rate and not for the primarypurpose. of establishing an anticipating feature.

Another object of theinvention is to eliminate noticeable lag in warm-uptimes upon a demand for heat in the space being conditioned.

Other objects and advantages will become apparent from the-following.description. taken. in connection with the accompanying drawings,wherein:

Fig. 1 is a schematic view of a panel heatin system having a. wiringdiagram incorporated therewith;

Fig. 2 isa cross section .of the temperaturecontrol devicefor the fuel.burner'shown schematically in Fig. 1; and a Fig. 3 is across.section.of one-of thecontro valves'shown schematically in-Fig. 1.v

Referring more particularly tow-thedrawings, Fig. 1 thereof depictsaheatingmeansfora fluid comprising a water heater equipped. with mainand pilot gaseous fuelburners l2 and. respectively. The water heater I0.is supplied with cold water under pressure from a main supply pipe 16which is connected to asuitablev source of supply such asa well, coolerormunicipal watersupply system. A manually operated shut-.- offvalvelBcontr01s=the flow of water inthe main pipe 16.

The flow of fuel to the main burner. l 2 and. pref.- erably, to thepilot burner l4 iscontrolled bya temperature control. device designated:g nerally by the. reference. numeral 20 and whichis. inter.- posed in amain fuel supply pipe 22; As shown in detail inFig. 2 of the-drawing,the temperature control device; 2 0 comprises amaincasing 24 having aninlet opening 26 for connectionto the main supply pipe 22 and an outlet,opening 28 for connection. to themain burner I2.

Thev main casing 24 adjacent the inlet. opening 26. is provided with atapered valve seat 3ll.for thev reception of a hollow taperedshut-oifcock-M for. controlling the passage of fuelv from; the inletopening 26to theinterior of themaincasing 24. In this embodiment theshut-off cock 3.2- is, also provided with apassageway (notshown) foraffordingcommunication between the inlet open.- ing25 and an outlet.opening 34. formed .inzthe casing. 24 and. with. which the pilot burner.14 communicates- The arrangement is such that when the cock 32 is in a.pilot position,v intermediate vfull-openand full-closed positions, thenflow of fuel from the main fuel pipe 22 to. the pilotburner I4 can occurwithout acorresponding flow of fuel through the cock 32.to the in teriorof the casing- 24.

The interior of the casing 24 is provided. with an annular valve seatmember 36 against which avalvemember 38; is biased by a coil spring intoclosed positionto prevent fuel flow to the outlet opening 28. The valvemember 38 is provided witha. valve stem 39 projectingintothe valve seatmember 36 and is movable towardan open position relative to the seat 36by .a. first temperature responsive means. Thus. a. tube 42 is mounted.in anipple extension 44 of. the main casing 24 and a rod .46 having alower coefficient of expansion than the tube.42 hasits outer endthreadedly connected to the tube 42.to.'complete the first temperatureresponsive means 4|. The rod. 46 is adapted upon contraction of the tube42 to exert a thrust through a cap. member 48 against a thrust member5llboth of .whichare positioned in the casing 24 on one side of thevalve member. 38. The thrust. member-5ll co operates: with a clicker.disc 7 52,. which engages perature as sensed by the bulb 62.

of heated fl-uid to the coils 88.

the valve stem 39 and a portion of the valve seat 38, to force the valvemember 38 toward open position against the bias of the coil spring 40.As snap-action devices of this nature are well known to the art, furtherdescription is deemed unnecessary. Temperature adjustment of the firsttemperature responsive means 4| may be effected through a lever 54 whichis secured to the inner end of the rod 46 and is operable to rotate therod 46 relative to the tube 42 and move it toward and away from the capmember 48.

The movement of the valve member 38 toward open position by the firsttemperature responsive means 4| is limited by a second temperatureresponsive means designated generally by the reference numeral 58 andpositioned on the opposite side of the valve member 38 to thefirst'temperature responsive means 4|. The second temperature responsivemeans 56'comprises an actuating element 58, a capillary tube 68 and abulb 62 which contain a thermal liquid of any suitable type for causingexpansion and contraction of the actuating element 58 upon changes intem- The actuating element 53 is supported in a cover 64 which serves asa closure for an opening 55 to the'interior of the casing 24 oppositethe valve seat 36. Movement of the actuating element 58 is commufnicatedto the valve stem 39 through a diaphragm element 86- which extendsbetween these members and is positioned by the cover 64 against the maincasing- 24 in sealing relation with the open ing'65 therein.

The temperature control device 28 is mounted in position on the waterheater l8 with-the nip- "p'le' extension 44 threadedly engaging the wallof the water heater IE3 and the tube 42 and rod 46 of the firsttemperature responsive means 4| projecting into the water being heatedtherein.

The bulb 62 of the second temperature responmatter, the amount ofopening movement of the valve member 38 and thus the rate of fuel supplyto the main burner 12 depend upon the outside temperature as sensed bythe bulb 62, it being apparent that the valve member 38 cannot be movedaway from the seat 36 any greater distance than is permitted by thediaphragm element 66.

Referring now further to Fig. 1 of the drawings, means are provided forcirculating fluid in heat exchange relation with the water heater I anda space to be heated. This circulating means includes a plurality, inthis instance two, of panel heating coils 68 located in different spacesto be heated and which coils are customarily imbedded in the ceilings,walls or floors of different rooms.

-A supply pipe 18 and a return pipe 12 are each connected at one endthereof to opposite ends of the coils 68 and the opposite ends of thepipes H3, 32 are both connected to the water heater l0.

Means responsive to temperature changes within-the spaces beingconditioned by the coils 68 is provided and is effective for controllingthe tem erature of the spaces by controlling the flow This meanscomprises a combined throttling valve and temperature sensitive elementdesignated generally as a "thermostatic valve 14 and shown in detail inFig.

3 of the drawings. The thermostatic valve '84 4 tition 82 is suitablyapertured to provide a passage 84 controlled by a valve member 86 havinga stem 38 projecting at one end into a bonnet member 98.

An expansible actuating member 92 is secured to the projecting end ofthe valve stem 88 and is subject to the pressure of a thermal liquidcontained within the actuating member 92 and within a capillary tube 94and bellows element 96 connected thereto in a closed system. The end ofthe capillary tube 94 adjacent the actuating element 92 communicateswith a hollow bushing 98 carried by the actuating member 92 and securedto the bonnet 98. The opposite end of the capillary tube 94 communicateswith the bellows 8B which may be positioned at any desired distance fromthe actuating member 92. The bellows element 98 is housed within acasing I08 and is en gaged at one end by an override spring I82supported in the casing I08 and, at the other end by an adjusting screw|84 which projects'exteriorly of the casing 80.

One of the thermostatic valves 14, as indicated in Fig. 1 of thedrawings, is provided for each coil 68 and is positioned with the valvebody 16 connected between the related panel coils 68 and the return pipe12 to control the flow offluid therein. Thus, the inlet 18 of each valve14 is connected to the coil 68 and the outlet 88 is connected to thereturn pipe 12. The casing I08 containing the bellows element 96 issecured in some convenient location within the space responsive tocondition of the related coils 68. The position of each valve member 86relative to the passage 84 will be controlled by the position of theactuating member 82 responsive to the thermal condition of the bellows86. It should be noted that a throttling or modulating type of controlis provided as will hereinafter be apparent. Upon a sufficient increasein the temperature to which the bellows 96 responds, as regulated by theadjusting screw :04, then the valve member 86 will be moved to closedposition relative to the passage 84 to shut off the flow of fluid fromthe inlet opening 18 to the outlet opening 88.

Circulation of the fluid from the water heater I0 through the flow andreturn pipes l8, 12 respectively is effected by the provision of a pumpI06 which is connected in the return pipe 12 between the coils 88 andthe water heater W. A check valve I88 is provided in the return pipe 72between the pump M5 and the coils 68 to insure the desired direction offiow. The flow of fluid between the water heater l8 and the coils 68 isunder control of flow controlling means comprising a first solenoidvalve H8 which is interposed at a convenient location between theseelements and is electrically operated upon energization of its coil illby means to be described hereinafter.

Provision is made for flushing the coils 68 with relatively cold waterfor limited periods when the outside temperature exceeds a certainpredetermined value. Thus, an upper by-pass pipe H2 is connected atoneend to the main inlet pipe |6 ahead of the water heater l0 and to thesupply pipe 10 at the opposite end, the latter connection beingintermediate the solenoid valve H0 and the coil 68. A lower by-pass pipe||4 has one end connected to the return pipe 12 between the check valveH18 and the thermostatic valve 14 and has its opposite end connected tothe return pipe 12 intermediate the pump 186 and the water heater l0.

The flow of fluidin the upper and lower bypass pipes H2 and H4isiunder'controlrofi flow controlling means comprising second and thirdsolenoid valves II6 and H8 respectively, which are electrically operatedupon energization of coils Ill and H3 respectively by means to bedescribed hereinafter. A drain connection I and a manually operatedshut-off valve I22 are provided in the lower by-pass pipe II4 betweenthe third solenoid valve H8 and theconnection of the by-pass pipe II4 tothe return pipe 12 adjacent the water heater I0.

Thermostatic switch means I24 are provided for controlling the operationof the flow-controlling .means comprising the solenoid valves H0, H6 andH8. The thermostatic switch means I24 includes a rotatable switch armI25 adapted to connect a pair of diametrically opposite contactmeansI26, I21 or, alternatively, another pair of diametrically oppositecontact means I26 and I29. Movement of the switch arm I25 into one crtheother of said cooperative positions is caused by responseofthe-thermostatic switch means I24 to changes in temperature exterior ofthe Spaces conditioned by the coils 68. In this instance, a thermalactuating element (not shown) for the switch arm I25 is connected by acapillary tube I30 to a bulb element I32 which is located outdoors torespond to the temperature at that location.

The system includes means to turn :the circulating pump I06 01f duringthe night hours and such means is shown as comprising a switch I34. Itwill be understood that a clock control (not shown) is included foroperating the switch I34 at preset times but as such devices are wellknown further description is deemed unnecessary. The switch I34 isarranged to'control the pump I06 only as permitted by a low temperaturecutoff thermostat I36 which, as will be hereinafter apparent,reestablishes the operation of the pump I06'if the temperature in thespaces being heated by coils 68 falls below a certain predeterminedtemperature for which the thermostat I36 is set. A thermostatic cut-outI38 is located at the motorof the pump I06 to respond to excesstemperatures at that point.

The flow of cooling fluid in. the .upper and lower by-passpipes I12 andH4 is'controlled by operation of a timing device which is shown heremerely as a switch I40. Such timing devices employ a low speed electricdrive from a synchronous clock motor (not shown) and normally -maintaina closed circuit position when deenergized. In this instance, the timingdevice including switch I40 is of the type which can be set to remainclosed for approximately five minutes upon energization, will open andremain open for approximately twenty-five minutes when energized andthen will automatically recycle. It will be apparent hereinafter thatimmediately upon closing of the circuit wherein it is connected, theswitch I40 will introduce a fiveminute period during which cold waterflushing for the coils 68 can be conducted. Further operation of theswitch I40, together with that of the remaining components of thesystem, will be apparent from the description of the operation of thetemperature control system, which now proceeds, it being noted that adescription of the I wiring diagram is now included.

In the operation of the system, it can be assumed that the thermostaticswitching device I24 is in the position shown in Fig. 1 of the drawingsand that the outside temperature to which the bulb I32 is responsive issuch as to cause theswitch arm' I25to remain. in the po sitionshown forclosing. thecontacts I26, I21 andestablishing a heating circuit. Itis'further assumed thatthe clock-operatedswitch I34 is also in theclosed position shown infull lines in the drawing. The thermostaticcut-out I38 is assumed to be responding to a temperature condition lowerthan that forwhich it is set to open and is therefore in the closedposition shown in the. drawings. Thus, upon closing of a doublepole mainswitch I42, a circuit is established as follows: linewire I44, upperpoleof main switch I42, wire I46, contact I 26, switch arm I25, contactI27, wire I48, switch I34, wire I50, wire I52, coil. I II, wire E54,wire I56, lower pole of main switch I42 and wire I58 to line wire I60.Such circuit will serve to energize the coil I I I and the solenoidvalve IIO will therefore open.

Simultaneously, a parallel circuit is established as follows: line wireI44, upper pole of main switch I42, wire I46, contact I26, switch armI26, contact I21, wire I48, switch I34, wire I56, wire I62, thermostaticcut-out I38, wire 54, pump I06, wire I66, wire I56, lower pole of mainswitch I42 and wire I58 to line wire I60. This circuit will serve toenergize the pump I06 for circulation of fluid through the coils 68.

The temperature setting of the first temperature responsive means 4icomprising tube 42 and rod 46 is adjusted by operation of the lever 54to a predetermined setting. Assuming that there is a demand for heat inthe fluid to be circulated by reason of the temperature thereof beinglower than the setting of the lever 54, then the first temperatureresponsive means 4| operates through the snap-action device 43, 50, 52to open the valve member" 36. The amount of opening movement of thevalve member 38, however, depends upon the position of the diaphragm-66which is positioned relative to the valve stem 39 by cooperation of theactuating element 58.

When the outside temperature to which the bulb 62 responds is above apredetermined minimum temperature, then the actuating element 58 willcorrespondingly limit the amount of opening movement available to thevalve member 38. With this reduced rate of fuel supply to the mainburner I2, the'recovery time of the water heater I!) is increased. Sincecontinuous circulation is employed in the system, the average watertemperature will tend to remain below the setting of the lever 54 untilthe heat demand is satisfied and the pump I06 deenergized by operationof the thermostatic switching device I24 responding to the outdoortemperature sensed by the bulb I32. Thereafter, the water in the waterheater I0 will continue to be heated until the temperature setting ofthe lever 54 is reached, whereupon operation of the first temperatureresponsive means 4! causes closure of the valve member 36 under bias ofthe spring 40.

It will be apparent that the net result of the foregoing action is thatthe rate of fuel supply to the main burner I2 and the temperature of thewater circulated to the coils 66 are varied in proportion to the totalheating demand of the space being heated by the coils 66 as'establishedby the outdoor temperature sensed by the bulbs 62 and E32. This actionis desirable as tending to prevent hunting or slow oscillations that canoccur due to the inertia of the structure being heated. The controlmodulates the supply of energy to the coils 68 and restricts the amountof energy which is available to a small range on either side of thenormal quantity corresponding to a given load. It will further beapparent that the control apparatus responsive to outdoor temperaturesis used as a means of selecting the basic energy rates and is not forthe primary purpose of establishing an anticipating feature.

The thermostatic valves 14 provide a throttling type of control toautomatically compensate for changes in the individual zone temperatureconditions. The devices are thus distinguished from the usual manuallyset and relatively inaccessible valves which require careful and tediousadjustment to obtain the desired heat balance conditions. Full use ismade in this invention of the modulating or throttling action of thevalves 14 in the intermediate positions of the valve members 86 and theresult is an improvement over the on-ofi type of operation customarilyobtained. In addition, these valves 14 automatically compensate forchanges in the heat input requirements caused by variable factors suchas solar radiation, shifting winds, open windows, supplemental heatsources such as fireplaces'and any other factors which might affect theheating requirements of the zone. It is apparent that the automaticadjustment of the valves 14 between open and closed positions for eithercomplete shut-off, throttling action or full-open flow eliminates theexpense involved in balancing or adjusting each individual zonemanually.

The described deenergization of the pump I06 by operation of thethermostatic switch means I24 will occur when the outside temperature towhich the bulb I32 responds exceeds a certain predetermined value forwhich the switch means I24 has been set. Consequently, the switch armI25 is operated to open the contacts I26, I21 and close the contactsI26, I29. Such operation will serve to open the circuit of the coil IIIof the solenoid valve H6 and also the circuit of the pump I06 aspreviously traced. The pump I66 thereupon ceases to circulate fluid tothe coils 68 and the flow of heated fluid from the water heater I to thesupply pipe is cut off by closing of the solenoid valve III].

In the new position of the switch arm I25 the following circuits areestablished: line wire I46, upper pole of main switch M2, wire I63,contact I28, switch arm I25, contact I29, wire I10, switch means I40,wire I12, coil II1, wire I10, wire I56, lower pole of main switch I52and wire I58 to line wire I60. This circuit will serve to energize thecoil H1 and the solenoid valve H6 thereupon opens.

, The other circuit established in the new position of the thermostaticswitch means I24 is as follows: line wire hi4, upper pole of main switchI42, wire I68, contact I28, switch arm I25, contact I29, wire I10,switch means I40, wire I76, coil H9, wire I18, wire I56, lower pole ofmain switch I42 and wire I58 to line wire I60. This circuit serves toenergize the coil H9 and the solenoid valve H8 thereupon moves to openposition.

As previously stated, the timing device M0 is in closed position whendeenergized and will remain in closed position for a limited period,such as five minutes, upon energization of the circuit to which it isconnected. Thus, for this limited period unheated fluid under pressurefrom the source of supply will be delivered to the coils 68 through theupper by-pass pipe II2, supply pipe 10 and coils 68 for flushingpurposes. The pressure of the fluid so delivered is sufficient to forcethe valve members 86 of the thermostatic valves 14 to their maximum openposition regardless of '8 the expanded position of the'bellows 96 andthe actuating members 92. Such operation will not damage the mechanisminasmuch as the override spring I02 serves to accommodate the addedexpansion of the bellows 96. After passing through the thermostaticvalves 14 the cooling fluid travels through the return pipe 12 to thelower Icy-pass pipe I I4 and is discharged through the drain connectionI20.

The timing device I40 provides the described cycling action for thecooling operation by opening the circuit of the coils II1, I I9 of thesolenoid valves H6, H8 after the five-minute period has elapsed andmaintaining these valves closed for the next twenty-five minutes. In theevent that the switch arm I25 remains in the new position for closingthe contacts I28 and I29, then a continued cycle of intermittent coldwater flushing for five-minute periods ensues. Upon return of the switcharm I25 to its original position for closing the contacts I26, I21, thenthe heating circuit will again be closed as previously described.

During the night-time the night clock switch I34 can be adjusted to openthe heating circuit previously traced and deenergize the pump I06 asdesired. Durin this period should the temperature in the space in whichthe thermostat I36 is located fall below that for which this thermostathas been set, then a shunt circuit is established around the night clockswitch I34 by wire I89 connected at one end to wire I48 and at theopposite end to the movable arm of the thermostat I36, and by wire I86connected at one end to contact I0 3 of the thermostat I36 and at theopposite end to wire I52. Such shunt circuit will, of course, serve tocause energization of pump I06 despite the open position of the switchI34.

It should be observed that the initial energization of the pump I06'tocirculate heated fluid to the coils 66 will result in circulation offluid which is hotter than that which is normally required to satisfyoutside temperature conditions. This quick-heat feature tends toeliminate the lag in warm-up times so noticeable with other types ofcontrol and is due to the valve member 30 of the temperature controldevice 20 remaining open for a limited period after the pump I06 is shutdown. As previously described, the valve member 38 is not permitted toclose under bias of the spring 40 until the first thermostatic meansactual room temperature as will be apparent. It

will be understood that many changes may be made in the details ofconstruction and arrangement of parts without departing from the scopepermitting said fluid flow, second temperature a responsive meansincluding an eXpa-nsible diaphragm element positioned on the oppositeside of said seat and having gradual movement relative to said valveseat, and means movable by said diaphragm to a plurality of difierentpositions in the path of said valve member under varying temperatureconditions affecting said 10 second temperature responsive means forlimiting the movement of said valve member to positions intermediatesaid fully open and fully closed and throttling said fluid flow.

. ROBERT C. MAIN.

REFERENCES ci'mn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,980,789 Dillman Nov. 13, 19342,262,194 Newton Nov. 11, 1941 2,358,637 Hawk et a1 Sept. 19, 19442,361,945 Jackson Nov. 7, 1944 2,383,401 Mantz Aug. 21, 1945

